var navette_left_1 = document.getElementById('navette_left_1');
var navette_right_1 = document.getElementById('navette_right_1');

function to_right()
{
	options = navette_left_1.getElementsByTagName('option');
	
	nb = options.length;

	for ( i=0 ; i < nb ; i++ ) {
		option = options[i];
		
		if (option.selected) {
			navette_right_1.appendChild(option);
			i = -1;
		}
			
	}
}

function to_left()
{
	options = navette_right_1.getElementsByTagName('option');

	nb = options.length;

	for ( i=0 ; i < nb ; i++ ) {
		option = options[i];

		if (option.selected) {
			navette_left_1.appendChild(option);
			i = -1;
		}

	}
}

function all_to_right()
{
	options = navette_left_1.getElementsByTagName('option');

	nb = options.length;

	for ( i=0 ; i < nb ; i++ ) {
		option = options[0];
		navette_right_1.appendChild(option);
	}
}

function all_to_left()
{
	options = navette_right_1.getElementsByTagName('option');

	nb = options.length;
	
	for ( i=0 ; i < nb ; i++ ) {
		option = options[0];
		navette_left_1.appendChild(option);
	}
}